1. Technical Field
The present invention relates to a valve timing adjusting apparatus of an internal combustion engine.
2. Background Art
In the field of valve timing adjusting apparatus for adjusting timing of opening and closing an intake valve or an exhaust valve of an internal combustion engine, when it is necessary to establish at least two regulation angles for regulating relative rotation of a housing and a rotor, a construction provided with one lock pin has been heretofore proposed for regulating relative rotation of the housing and the rotor for each regulation angle, as disclosed in the Japanese Patent Publication (unexamined) No. 227236/1998. That is, the apparatus has been constructed to have two lock pins when two regulation angles are established.
Fabrication of the regulation angles and accuracy in positioning them on a lock pin storing side as well as on an engaging side are secured by machining. Therefore, a problem exists in that it is necessary to fabricate two regulation angles accurately on each of the lock pin storing side and the engaging side in manufacturing the conventional apparatus.
The present invention was made to resolve the above-discussed problems and has an object of obtaining a valve timing adjusting apparatus of an internal combustion engine in which number of lock pins is decreased by regulating relative rotation at two places using the same lock pin which regulates relative rotation of both housing and rotor.
A valve timing adjusting apparatus of an internal combustion engine according to the invention comprises: a housing which is mounted on a camshaft of the internal combustion engine so as to be relatively rotatable, has a plurality of fluid chambers partitioned by shoes inside, and is driven synchronously by a crankshaft of the internal combustion engine; a rotor which is mounted on the camshaft and has a plurality of vanes for partitioning the plurality of fluid chambers into advancing chambers and/or retarding chambers respectively; a lock pin which is stored in the rotor and is urged so as to be movable toward the housing; and first and second engaging portions which are formed on the housing at different positions of relative rotation of the rotor with respect to the housing and respectively face the lock pin; in which the rotor is regulated to be at the different positions of relative rotation with respect to the housing by engaging the same lock pin with the first and second engaging portions respectively. As a result, number of the lock pins can be decreased and the housing can be small-sized.
It is preferable that the apparatus further comprises an advancing chamber oil passage for applying oil pressure to the advancing chambers and a lock pin oil passage for applying oil pressure to move the lock pin against urging force that urges the lock pin. As a result, it is possible to control the apparatus with oil pressure, decrease number of the lock pins, and obtain a small-sized housing.
It is preferable that oil pressure is applied to the lock pin oil passage independently of the advancing chamber oil passage. As a result, the lock pin is controlled easily and accurately.
It is preferable that the lock pin oil passage is provided with a control valve for controlling application and release of oil pressure to the lock pin oil passage. As a result, the control becomes accurate.
It is preferable that, by applying oil pressure to the lock pin oil passage, an end of the lock pin and the first engaging portion are disengaged and the other end of the lock pin and the second engaging portion are engaged. As a result, the disengagement of the lock pin with the first engaging portion (for example, extracting direction) and the engagement of the lock pin with the second engaging portion (for example, inserting direction) are both performed in the same direction. Thus, response characteristic is improved, and control can be performed with less switching of oil pressure.
It is preferable that each of the fluid chambers is partitioned into the advancing chamber and the retarding chamber with vanes of the rotor, and the retarding chamber is provided with a retarding urging member. As a result, return response characteristic to the retarding side is improved.
It is preferable that the regulating positions of relative rotation of the rotor with respect to the housing are established to be at a maximum retarding position and an approximately intermediate angle position within a variable angular range of relative rotation of the rotor. As a result, it is possible to make a delicate control.
It is preferable that the lock pin has an integral configuration in which plural cylinders are coaxially arranged. As a result, the lock pin is fabricated easily.
It is preferable that an end of the lock pin is engaged with the first engaging portion of the housing and the other end of the lock pin is engaged with the second engaging portion of the housing. As a result, the disengagement of the lock pin with the first engaging portion (for example, extracting direction) and the engagement of the lock pin with the second engaging portion (for example, inserting direction) are both performed in the same direction. Thus, response characteristic is improved, and control can be performed with less switching of oil pressure.
A valve timing adjusting apparatus of an internal combustion engine according to the invention comprises: a housing which is mounted on a camshaft of the internal combustion engine so as to be relatively rotatable, has a plurality of fluid chambers partitioned by shoes inside, and is driven synchronously by a crankshaft of the internal combustion engine; a rotor which is mounted on the camshaft and has a plurality of vanes for partitioning the plurality of fluid chambers into advancing chambers and retarding chambers respectively; a lock pin which is stored in the rotor and is urged so as to be movable toward the housing; first and second engaging portions which are formed on the housing at different positions of relative rotation of the rotor with respect to the housing and respectively face the lock pin; a first oil passage for applying oil pressure to the advancing chamber; a second oil passage for applying oil pressure to the retarding chamber; and a third oil passage for applying oil pressure which moves the lock pin against urging force that urges the lock pin; in which the rotor is regulated to be at the different positions of relative rotation with respect to the housing by engaging the same lock pin with the first and second engaging portions respectively, and one end of the lock pin and the first engaging portion are disengaged and the other end of the lock pin and the second engaging portion are engaged by applying oil pressure to the third oil passage. As a result, number of the lock pins is decreased and the housing is small-sized. Accurate control is achieved because the advancing chamber is controlled by the first oil passage and the retarding chamber is controlled by the second oil passage, and balance of the two separate controls makes the entire control.
A valve timing adjusting apparatus of an internal combustion engine according to the invention comprises: a housing which is mounted on a camshaft of the internal combustion engine so as to be relatively rotatable, has a plurality of fluid chambers partitioned by shoes inside, and is driven synchronously by a crankshaft of the internal combustion engine; a rotor which is mounted on the camshaft and has a plurality of vanes for partitioning the plurality of fluid chambers into advancing chambers respectively; a first lock pin which is stored in the rotor and is urged so as to be movable toward the housing; first and second engaging portions which are formed on the housing at different positions of relative rotation of the rotor with respect to the housing and respectively face the first lock pin; a second lock pin which is stored in the rotor and is urged so as to be movable toward the housing; and third and fourth engaging portions which are formed at positions of the third and fourth relative rotation which are different from the positions of the first and second relative rotation on the housing and respectively face the second lock pin; in which the rotor is regulated to be at positions of multistage relative rotation with respect to the housing by engaging the first lock pin with the first and second engaging portions respectively and engaging the second lock pin with the third and fourth engaging portions respectively. As a result, it is possible to make a delicate control. Number of the lock pins can be decreased due to multistage control, and the housing can be small-sized.